The present invention relates to apparatus for the continuous finishing liquid treatment of full-width material webs, in particular textile webs, such as woven or knitted webs, tufted textile webs, fiber fleeces, yarn slivers, fiber rovings and the like.
In the continuous finishing treatment of textiles it is a paramount principle that a constant maintained quanity of a liquid containing the finishing media or agents in a constantly maintained concentration is applied to the web to be treated such as, for example, a foulard fabric, in a suitable finishing apparatus. In such treatment the volume of the bath through which the web is passed must be as small as possible in order that it can be continuously renewed from the continuously flowing treatment medium.
The particular processing medium used is in such cases usually applied at a low or medium temperature. Apart from some cold steeping techniques and methods in which the web impregnated with the processing medium is subsequently dried, the treatment is concluded with processing in moist heat, preferably water vapor, in which the web and the applied processing medium are conjointly heated to a suitable reaction temperature and held at such temperature for a specified time. This technique, of continuously applying a process medium at low or medium temperature in controlled quantity with ensuing conjoint heating of the process medium and the processed material to an optimum temperature and subsequent holding at that temperature, is usual today in continuous finishing and in certain dyeing treatments in which absolute consistency of the concentration of the process medium applied to the textile material from beginning to end of a particular batch, is required.
Owing to this requirement, continuous finishing treatment in hot processing liquids with a necessarily large volume which are, as a rule, heated independently of the material web being treated, with the impregnation by the process medium and the treatment by reaction heat being combined in a single operation, has hitherto been restricted to lower quality requirements or methods, the results of which are not so greatly dependent on the particular concentration of the treating bath.
To solve these problems, efforts have been made in the prior art to greatly reduce the volume of treatment liquid. In the so-called Williams unit, displacement elements are inserted between the vertical web guides. However, this unit can only be used, for instance in continuous dyeing, either for batches of more than 10,000 meters, or if the requirement for uniform end-dyeing is relaxed. Consequently, despite its great inherent advantages, continuous hot-liquid treatment has not come into general use in competition with the batch processes involving separate application of the finishing media with following heating and holding at elevated temperature.